The present invention relates to cables for transporting power and for telecommunications, and that have been structurally reinforced by incorporating at least one reinforcing wire and/or armoring made up of one or more layers of wire.
In conventional manner, numerous power transport cables and telecommunications cables are structurally reinforced in order to enable them better to withstand the physical stresses that might be applied to them in the medium in which they are installed. In overhead cables, this leads to one or more reinforcing wires being associated with the electrically conductive wires and/or with the light-transmitting waveguides in order to improve the performance of such cables in mechanical terms, and in particular in terms of breaking strength. In similar manner, it is conventional to provide mechanical reinforcement for land cables, in particular those which are designed to be buried, and also for underwater cables, by means of armoring made up of one or more layers of wires that are mechanically stronger than the electrically conductive wires and/or the transmission waveguides that the armoring surrounds.
The reinforcing wires and the armoring wires of power transport cables and of telecommunications cables can be made of stainless steel so as to take advantage of the mechanical qualities that can be obtained with such steels and also of their ability to withstand corrosion. A high degree of resistance to corrosion is essential, in particular for undersea cables which are placed in a corrosive medium, and also for underground cables and overhead cables that are subjected to difficult climatic constraints. Thus, document EP-A-710862 describes an undersea optical fiber cable having stainless steel reinforcing wires.
Nevertheless, the use of stainless steel for making reinforcing wires or armoring wires gives rise to a significant increase in the cost of such cables, and less expensive substitute solutions are therefore being sought.
It is known to replace stainless steel wires with other wires, in particular galvanized steel wires or steel wires protected by an aluminum coating, for the purpose of reducing cost. Nevertheless, the resulting resistance to corrosion is considerably less and the way hydrogen can be given off, particularly from galvanized steel wires, means that such wires cannot be used to make the cores of optical fiber cables for telecommunications.
The invention therefore proposes a power transport cable or a telecommunications cable that is structurally reinforced by incorporating at least one reinforcing wire and/or armoring having one or more layers of wires.
According to a characteristic of the invention, the cable has at least one reinforcing or armoring wire made of composite steel having a steel core of standard type, and covered in a layer of stainless steel.
According to a characteristic of a variant of the invention, the cable has at least one layer of armoring constituted by composite steel wires.
According to a characteristic of a variant of the invention, the cable has at least one reinforcing wire or armoring wire constituted by composite steel sold under the registered trademark NUOVINOX.
According to a characteristic of a variant of the invention, the cable has a tube obtained from a sheet constituted by composite steel having a core of a standard type of steel covered in a layer of stainless steel.
According to a characteristic of a variant of the invention, the cable has a tube constituted by a composite steel sold under the registered trademark NUOVINOX.